"Le livre noir est joli."
Earlier "joli" was translated as "attractive", but on this page it was marked incorrect.
I totally think books can be attractive, as the word can simply mean "aesthetically pleasing". Hmm...
for a book, 'attractive' here is not adequate so 'nice' while be enough. The poor black book :)
'joli' also can be translated to pretty, cute, etc
In British English, saying a book is attractive is legitimate, however it is formal and not commonly used.